This invention relates to an exhaust system for a marine propulsion unit and more particularly to an improved exhaust system for a small watercraft.
In many forms of watercraft it is a common practice to discharge the exhaust gases from the powering internal combustion engine into the body of water in which the watercraft is operating. This is done for a wide variety of purposes, not the least of which is the effective silencing of the exhaust gases. Although such an exhaust gas discharge is extremely convenient for many operations, it is also essential that the exhaust system provide an arrangement wherein the water from the body of water in which the watercraft is operating cannot reenter the engine through the exhaust system.
Even when the watercraft employs an above-the-water exhaust, there are many conditions when water may enter the above-the-water exhaust discharge opening and it is important to insure that water cannot enter the engine through its exhaust system even with such an above-the-water exhaust gas discharges.
In addition to the problem of water entering the exhaust system from the body of water in which the watercraft is operating, it is also a common practice with marine propulsion units to discharge at least some of the coolant from the engine into the exhaust system. This has the advantages of offering a convenient water discharge from the engine cooling system and also aids in cooling and silencing the engine exhaust gases. Again, however, it is important to insure that the water does not enter the engine combustion chamber through the exhaust system when such discharges are employed.
It is, therefore, a principle object of this invention to provide an improved exhaust system for a marine propulsion unit.
It is a further object of the invention to provide an exhaust system for a marine propulsion device wherein water is not permitted to enter the engine combustion chambers through the exhaust system.
It is a further object of this invention to provide an improved water exhaust separating system for the exhaust system of a marine propulsion device.
One particularly popular form of small watercraft is powered by a jet propulsion unit and is designed so as to be operated by a single rider. This type of watercraft is extremely maneuverable and because of its sporting nature, it is common for the watercraft to become capsized during its operation. Hence, the exhaust system for such watercraft further increase the problems of preventing the ingestion of water into the engine through its exhaust system. It is, therefore, yet a further object of this invention to provide an improved exhaust system for such a small watercraft.